Despite decades of research, metastatic malignant melanoma remains an incurable disease. Only a small percentage of patients diagnosed with metastatic disease exhibit a clinical response to chemotherapy. Fewer still are cured. The five-year survival rate for those with metastatic disease ranges from 5-18%. Therefore, the focus of this study is to identify those genetic changes within melanoma, confirmed through functional genomic screening and in vivo validation, which provide a context of genetic vulnerability that can be exploited in advanced disease. Specifically, the applicant is proposing to perform high-throughput functional RNA interference (RNAi) screen to systematically identify genes that mediate melanoma cell sensitivity (Specific Aim 1). Subsequently, those targets identified will be validated (Specific Aim 2) by confirming siRNA-mediated gene knockdown in vitro, performing high-content mechanistic assays to elucidate the mechanism by which these genes mediate melanoma cell sensitivity in vitro, and evaluating the effectiveness of inhibiting these genes in vitro in combination with the selecting agent. Finally, the applicant will evaluate whether validated genetic targets can add to molecularly-informed combination therapies in vivo against xenograft models of melanoma (Specific Aim 3). The applicant hypothesizes that this functionally-based genomic approach will identify the context of genetic aberrations associated with tumor progression that are critical to rendering melanoma cells more resistant to chemotherapy. These validated genes could facilitate the combined targeting of these tumor-context vulnerabilities and could be of direct relevance to clinical exploitation. PUBLIC HEALTH RELEVANCE: The long-term prognosis for those afflicted with advanced stage metastatic melanoma is bleak, with a five-year survival rate ranging from 5-18%. The proposed research aims to identify genetic vulnerabilities acquired by metastatic melanoma cells that may be exploited to improve the effectiveness of clinical intervention in this disease.